This invention relates generally to a lifting adapter for bulk bags and more specifically to a new and improved lifting adapter for use in lifting, moving and releasing large bulk bags in a storage position to a remote manufacturing location.
With the advent of large containers for the shipment of bulk materials from one location to another, there was introduced into this country approximately twenty to twenty five years ago, large square woven polypropylene bags for this purpose. These bulk bags had a capacity ranging from twenty cubic feet up to seventy cubic feet and would vary in size from thirty-five inches wide by thirty-five inches long by twenty-three inches high up to the same width and length bag having a height of eighty-two inches unfilled.
These bags were constructed with bag lifting loops on the top of the bag which were used for transporting the bags from one location to another. The lifting loops were also used for holding the bags while they were being filled in a filling machine. The bag lifting loops were generally constructed of a strong web-like material which was sewn onto the upper corners of the square bag.
With the introduction of these bags, bag filling machines were developed to fill these large bulk bags and to remove them from the filling machine. Since the filled bags weighed as much as two thousand pounds, the heavy bag had to drop from restraining devices that held the bag in the filling machine.
When the bag was filled, a portion of the two thousand pound weight was applied to the bag loops. This resulted in difficulty in getting the bag loop from the restraining device holding the bag in the machine. The bag loops would tend to hang upon the various rods or hooks used since many times the material being filled in the bag was a sticky material and the environment around the filling machine was one of a dust laden atmosphere containing the sticky material.
In FIGS. 1 and 2 of the drawings of the applicant's before described U.S. Pat. No. 4,676,284, there is shown several of the prior art bag filling machines shown holding the large bulky bags. In the same U.S. Pat. No. 4,676,284, there is shown in FIGS. 3-10 of the drawings and there is described in the patent, the applicant's unique solution to the problems using novel releasable supporting arm holding devices which were inclined towards the center of the bulk bag. This novel arm design served as the forerunner of later developed restraining devices that were often called bag loop latches in the trade.
The applicant's bag filling machine with releasable supporting arms or latches was very satisfactory for use in certain required situations and was well accepted commercially in the marketplace. The applicant's machine was originally designed with four fixed latches in each corner of the machine. This required a worker to lean into the machine from various positions to hang the bag loops on the latches. In the alternative, the worker would have to move around the machine to place the loops on the latches resulting in more time required to set up the machine for filling the bag.
It was also found that the applicant's bag filling machine was often placed in a crowded shop environment which did not easily give the worker access to moving around the machine and he would then have to lean into the machine to place the bag loops on the latches resulting in safety problems.
It was also discovered that many bag filling operations desired to use several sizes of bags which were not able to be handled by the applicant's original design. While this original unique bag machine had vertical provisions for variations in bag length, the fixed corner latch mechanisms of the filling machine permitted only one bag size in the horizontal periphery of the bag.
As a result, the applicant designed additional bag filling machines with new and improved bag loop latch constructions on his machines. These can be seen in the applicant's U.S. Pat. No. 5,036,893 before referenced and in his pending U.S. patent application Ser. No. 07/692,693. Reference should be made to these patents and applications as well as the prior art cited in those patents and applications for the various latch constructions used.
The large bulk bags that are filled with filling machines as designed by the applicant and others are then usually transported internally, in the manufacturing environment, to an internal storage site using various overhead cranes and/or fixed restraining adapter devices for use on the cranes. In many cases, the large filled bulk bags are stacked two-high in storage. This requires the second bag to be placed on top of the first stored bag at a distance of six to eight feet in the air.
When this occurs, the top of the second bag would be approximately ten to twelve feet above the ground. This large distance above the floor made a manual release from the lifting adapter for the top bag difficult. The bag loops on the crane or lifting adapter were too high to reach by a worker from the floor in order to unlatch the loop from the crane adapter. The distance of approximately ten to twelve feet for the top bag was also unsafe for a worker to reach since he had to crawl on top of the upper bag in order to be able to release the bag loops.